Nature of Business and Summary of Significant Accounting Policies - Capital Allocation Plan, Equity Offerings and Share Repurchases (Details) $ / shares in Units, shares in Millions					3 Months Ended		6 Months Ended	12 Months Ended
	Nov. 19, 2015 $ / shares	Jul. 30, 2015 $ / shares	May. 20, 2015 $ / shares	Feb. 04, 2015 USD ($) $ / shares	Jun. 30, 2014 $ / shares shares	Mar. 31, 2014 $ / shares shares	Jun. 30, 2014 offering	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Class of Stock [Line Items]
Share repurchase program, authorized amount | $				$ 250,000,000
Number of shares repurchased | shares								4.6
Shares repurchased, value | $								$ 63,000,000		$ 200,000,000
Share price (in dollars per share) | $ / shares								$ 13.60
Dividends declared (in dollars per share) | $ / shares	$ 0.05	$ 0.05	$ 0.05	$ 0.05
Dividends declared | $								$ 65,500,000
Cash dividends paid | $								$ 49,300,000	$ 0	$ 0
Number of shares sold by Selling Shareholders | shares					43.7	30.0
Number of secondary public offerings | offering							2
Shares sold by Selling Shareholders, price per share (in dollars per share) | $ / shares					$ 10.45	$ 9.85
Stockholders [Member]
Class of Stock [Line Items]
Number of shares sold by Selling Shareholders | shares					43.7	30.0
Shares sold by Selling Shareholders, price per share (in dollars per share) | $ / shares					$ 10.45	$ 9.85